In printers that can print on both sides of a printer paper, depending on the print unit, the paper is turned over and sent into the print unit again after printing on one side of the paper. In this manner, printing is performed by the print unit on the other side of the paper, and double-sided printing is realized.
The turning over of the paper is, for example, performed in the following manner. First, a paper that has been printed on one side is fed in a forward direction along the discharge route. Then, while the paper is being fed in a forward direction along the discharge route, the direction of movement of the paper is reversed and the paper is fed in the reverse direction. The paper fed in the reverse direction is then sent into the turnover route for turning over the paper.
When reversing the direction of movement for turning over the paper, there are cases when the paper cants diagonally relative to the direction of movement. When the paper cants diagonally, it becomes difficult to print the image appropriately. At this point, it is desirable to detect that the paper has canted diagonally.
For example, in Patent Literature 1, the degree to which the paper is diagonal is detected by detecting the edge face position of the feed direction of the paper using two sensors in different positions in the width direction and orthogonal to the feed direction of the paper.